The present invention relates to processing microelectronic workpieces and handling such workpieces within an environment of a processing machine.
Microelectronic devices, such as semiconductor devices and field emission displays, are fabricated on and/or in microelectronic workpieces using several different apparatus (xe2x80x9ctoolsxe2x80x9d). Many such processing apparatus have a single processing station that performs one or more procedures on the workpieces. Other processing apparatus have a plurality of processing stations that perform a series of different procedures on individual workpieces or batches of workpieces. The workpieces are generally handled within the processing apparatus by automatic handling equipment (i.e., robots) because microelectronic fabrication requires extremely clean environments, very precise positioning of the workpieces, and conditions that are not suitable for human access (e.g., vacuum environments, high temperatures, chemicals, etc.).
An increasingly important category of processing apparatus are plating tools that plate metals and other materials onto workpieces. Existing plating tools use automatic handling equipment to handle the workpieces because the position, movement and cleanliness of the workpieces are important parameters for accurately plating materials onto the workpieces. The plating tools can be used to plate metals and other materials (e.g., ceramics or polymers) in the formation of contacts, interconnects and other components of microelectronic devices. For example, copper plating tools are used to form copper contacts and interconnects on semiconductor wafers, field emission displays, read/write heads and other types of microelectronic workpieces. A typical copper plating process involves depositing a copper seed layer onto the surface of the workpiece using chemical vapor deposition (CVD), physical vapor deposition (PVD), electroless plating processes, or other suitable methods. After forming the seed layer, copper is plated onto the workpiece by applying an appropriate electrical field between the seed layer and an anode in the presence of an electrochemical plating solution. The workpiece is then cleaned, etched and/or annealed in subsequent procedures before transferring the workpiece to another apparatus.
Single-wafer plating tools generally have a load/unload station, a number of plating chambers, a number of cleaning chambers, and a transfer mechanism for moving the microelectronic workpieces between the various chambers and the load/unload station. The transfer mechanism can be a rotary system having one or more robots that rotate about a fixed location in the plating tool. One existing rotary transfer mechanism is shown in U.S. Pat. No. 6,136,163 issued to Cheung, et al., which is herein incorporated by reference in its entirety. Alternate transfer mechanisms include linear systems that have an elongated track and a plurality of individual robots that can move independently along the track. Each of the robots on a linear track can also include independently operable end-effectors. Existing linear track systems are shown in U.S. Pat. No. 5,571,325 issued to Ueyama, et al., PCT Publication No. WO 00/02808, and U.S. patent application Ser. Nos. 09/386,566; 09/386,590; 09/386,568; and 09/759,998, all of which are herein incorporated in their entirety by reference. Many rotary and linear transfer mechanisms have a plurality of individual robots that can each independently access most, if not all, of the processing stations within an individual tool to increase the flexibility and throughput of the plating tool.
The processing tools used in fabricating microelectronic devices must meet many performance criteria. For example, many processes must be able to form components that are much smaller than 0.5 xcexcm, and even on the order of 0.1 xcexcm. The throughput of these processing tools should also be as high as possible because they are typically expensive to purchase, operate and maintain. Moreover, microelectronic processing tools typically operate in clean rooms that are expensive to construct and maintain. The throughput, and thus the value of most processing tools, is evaluated by the number of wafers per hour per square foot (w/hr/ft2) that the processing tool can produce with adequate quality. Therefore, plating tools and many other processing tools require fast, accurate transfer mechanisms and an efficient layout of processing chambers to accomplish acceptable throughputs.
One concern of existing processing apparatus is that the wafers may collide with one another as the transfer mechanism handles the wafers within a tool. Because many processing apparatus have a plurality of individual robots that move independently from each other to access many processing chambers within a single apparatus, the motion of the individual robots must be orchestrated so that the workpieces do not collide with each other or components of the tool. This typically requires complex algorithms in the software for controlling the motion of the workpieces, and the complexity of the software often necessitates significant processor capabilities and processing time. The complex algorithms accordingly increase the cost of the processing tools and reduce the throughput of workpieces. Additionally, errors in determining the position of the workpieces, executing the software, or calibrating the system can result in collisions between workpieces. Thus, it would be desirable to avoid collisions with workpieces in a manner that does not adversely impact other parameters of the processing apparatus.
Another concern of existing processing apparatus is that they tend to increase in size to handle larger workpieces. For example, as the industry moves from 200 mm. workpieces to 300 mm. workpieces, the tools required to handle the workpieces tend to become larger. As the tools become larger, they tend to occupy more clean room floor space which increases the cost of housing and supporting the tools.
Still another concern of existing processing apparatus is that the transfer mechanisms typically have complex mechanical and electrical assemblies with several components. This increases the risk that a component may malfunction, causing downtime of the entire processing machine and/or collisions that damage the workpieces. Therefore, it would be desirable to reduce the complexity of the transfer mechanisms.
Yet another aspect of existing transfer mechanisms is that they may not provide sufficient freedom of motion of the workpieces. Although many robots have been developed that have six degrees of freedom, many of these robots are not used in processing apparatus for fabricating microelectronic workpieces because the additional degrees of freedom increase the complexity of the systems. As a result, many existing transfer mechanisms limit one or more motions of the robots, such as limiting the vertical motion of the robots. It will be appreciated that it would be desirable to maintain the freedom of motion for the robots while also reducing the probability of collisions between the workpieces and the complexity of the robots.
The present invention is directed toward transfer devices for handling microelectronic workpieces, apparatus for processing microelectronic workpieces, and methods for manufacturing and using such devices. Several embodiments of integrated tools comprise a single robot, dual end-effector transfer device that is expected to increase the flexibility of designing integrated tools. Such tools can include plating chambers configured to electrolytically or electrolessly apply conductive materials to the microelectronic workpieces. In other embodiments, the tools can include other processing stations that perform other processes on the microelectronic workpieces, and that are accessed by a single robot. By using a single robot, less space is needed within the cabinet for the robot. As a result, more space can be used for the processing chambers or stations so that larger processing chambers can be used in the same or very similar foot print as smaller chambers. This is useful as many device fabricators transition from using 200 mm wafers to 300 mm wafer because 300 mm tools can be used in approximately the same area as 200 mm tools, and the 300 mm tools can have the same number of processing chambers as the 200 mm tools. Thus, several embodiments of single robots with dual end-effectors in accordance with the invention allow designers to more easily replace 200 mm tools with 300 mm tools. In several further embodiments, the dual end-effectors can have a common axis of rotation, which can further reduce the space occupied by the robot and required by the robot for movement.
Another feature is that each of the end-effectors of the single robot can service processing chambers in either row inside tool. The integrated tools can accordingly have several different configurations of processing chambers that can be assembled on a xe2x80x9ccustom basis.xe2x80x9d The processing chambers can have a common configuration so that different types of processing chambers can be mounted to the tool within the cabinet. By providing a robot with two end-effectors that have a significant range of motion, each end-effector can access any of the processing chambers so that the configuration of the processing chambers in the tool is not limited by the motion of the robot and/or the end-effectors. Therefore, the processing chambers can be arranged in a configuration that affords an efficient movement of workpieces through the tool to enhance the throughput.
The throughput of finished workpieces is also expected to be enhanced because the workpieces cannot collide with each other or another robot in the tool when a single robot with dual end-effectors is used. The robot can accordingly be a high-speed device that moves quickly to reduce the time that each workpiece rests on an end-effector. Additionally, the robot can move quickly because it does not need complex collision-avoidance software that takes time to process and is subject to errors. The single robot can accordingly service the processing stations as quickly as a dual robot system with single end-effectors on each robot. In several embodiments of the invention, therefore, the combination of having a fast, versatile robot and a flexible, efficient arrangement of processing stations provides a high throughput (w/hr/ft2) of finished workpieces.
In an aspect of one embodiment, a transfer device can include a transport unit configured to move along a linear track and an arm assembly operatively coupled to the transport unit. For example, the transfer device can further include a lift assembly carried by the transport unit, and the arm assembly can be coupled to the lift assembly. The arm assembly can include an arm actuator carried by the lift assembly to move along a lift path and an arm carried by the arm actuator to rotate about the lift path. The arm can include an extension projecting from one side of the lift path. The arm actuator can rotate the arm about the lift path to position the first and second extensions relative to processing stations of an apparatus. The transfer device can also include a first end-effector and a second end-effector, each being rotatably coupled to the extension of the arm to rotate independently of each other.
In another aspect of certain embodiments, the first end-effector is spaced above the arm by a first distance, and the second end-effector is spaced above the arm by a second distance. The first distance is different than the second distance to space the first end-effector at a different elevation than the second end-effector. The different spacing of the first and second end-effectors relative to the arm allows the device to carry two workpieces in a superimposed relationship without the potential of a collision between the workpieces. The first end-effector can be driven by an inner shaft and the second end-effector can be driven by an outer shaft disposed coaxially outwardly from the inner shaft so that the rotational motion of the first end-effector can be independent of the rotational motion of the second end-effector, though both end-effectors can rotate about a common axis. Several additional embodiments and alternate embodiments of devices, systems and methods are also included in the invention.